Organopolysiloxane compositions, which remain stable and free flowing during shelf storage in a sealed condition, but when exposed to ambient air, cure into rubbery elastomers at room temperature under the action of humidity are known in the art as room temperature vulcanizable (RTV) organopolysiloxane compositions. They have been widely used as sealants, coatings, and adhesives in building, machinery, electrical and other industrial fields.
RTV organopolysiloxane compositions are generally classified into the acetate type, oxime type, alcohol type, hydroxyamine type, and amine type depending on the type of compound to be eliminated. The compositions of the acetate, oxime, hydroxyamine, and amine types are undesirably corrosive to the surrounding metal while the compositions of the alcohol type, become unlikely to cure after long-term storage.
To overcome these drawbacks, Japanese Patent Application Kokai No. 11953/1979 proposes an RTV organopolysiloxane composition which is shelf stable and does not corrode the surrounding metal. This composition, however, tends to yellow under the influence of ultraviolet rays and heat and does not cure under acidic conditions since the curing catalyst is a guanidine compound.
There is a need for a curing catalyst which can be added to RTV organopolysiloxane compositions, to render them non-corrosive to metals, shelf stable, discoloration resistant, and curable under acidic conditions.